Interestingly, back in those days, Southfields was also a BR▸ station (I think it even had the BR logo outside) but it had no mainline services. I presume this was because BR empties would use the East Putney-Wimbledon section.
Thread drift alarm sounds...
Yes - the East Putney to Wimbledon section wasn't 'sold' (and it was only a token amount apparently) to LU until around '95 in the run up to privatisation, and up until then the stations appeared to be BR run, but as you say with no service. However even today the line is 'operated' by
NR» on behalf of LU, as the signalling is still to NR standards and controlled by Wimbledon ASC. Oddly, the platforms in Wimbledon station used by LU are still owned by NR. I'd be very surprised if NR weren't the responsible signalling maintainers as well - it would be unusual if there was a split responsibility. Another oddity is that there are LU train stops on the stop signals, but
SWT▸ don't have the train borne equipment - that goes against the popular belief that mainline stock cannot operate on LU without trip cocks being fitted.
Nowadays SWT still have a couple of passenger services that run over the route, (albeit at pretty unsocial times), mainly for route retention purposes, but at my last count there were also about 7 or 8
ECS▸ moves during the interpeak period. The main practical reason being that a train leaving Waterloo and heading down the main slow line through Earlsfield is on the wrong side of the tracks to get into Wimbledon Park depot, whereas a down train via Wandswoth Town, then East Putney and Southfields etc can be fitted into LU's offpeak timetable with little problem and obviously no crossing conflicts.
Once in a while during engineering work SWT have run a fairly frequent mainline service over the East Putney route - indeed a couple of years ago I did the route both ways - and LU ran a reduced service to make space for the diversions. There is a major question mark over SWT's access though as the route is almost certainly going to be resignalled as part of the sub surface lines upgrade by 2018, and with an LU style
ATO▸ system it is likely that SWT will no longer be welcome.
Paul